I have a pre-ban lower and it makes sense to use it as a tactical carbine. I plan on going with a bushmaster A3 upper 16" fluted ( shorty or v match w/milled frontsight). if I use some sort of optic will the front sight get in the way or should I go with flip up front and rear sight.

A "tactical carbine" needs a front sight, and IMO it should be a fixed front sight. Most non-magnified "dot"/"reflex" optics are designed to work well with the iron sights, allowing them to be "co-witnessed" so that if the optic fails, the iron sights are usable. When using a magnified optic, the focal length leaves (at worst) a shadow at the bottom of the scope that you can see right through. A number of rear Back-Up Iron Sights (BUIS) are available, with the strong favorite being the excellent ARMS #40 flip-up.
I also recommend against the V-Match for this use, as the non-vented aluminum handguard is designed for match shooting, and gets far too hot to hold during sustained fire. The standard handguards will work fine, and if you want something better later on, you can get a quality vented & railed handguard setup from Knights or ARMS to suit any need.
-Troy

I use mine for 3-gun matches and for tactical use. I have a Holo sight mounted. I dont use the flip up iorn sights, but have them there for backup use.
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